High pressure enclosed arc device



G.- s. SPERTI 2,369,987

HIGH PRESSURE ENCLOSED ARC DEVICE Filed Sept. 17, 1941 Feb. 20, 1945.

' mvmon 6150/3615 5'. Spa- 7 ATTORNEYS.

Patented Feb. 20, 1945 UNITED -STA'IIES PATENT OFFICE men PRESSURE :l: CI:SED ARC nmcn George S. Spertl, Oovington, Ky., assignor, by

mesne assignments, to The Institntnm Divi Thomae, Foundation, Cincinnati, Ohio, a corporation of Ohio Application September 17, 1941, Serial No. 411,217

9.01aims. (c1. 176-422) ficient to maintain a relatively high pressure of mercury or the like withinsthe envelope during periods of operation whereby the arc partakes oi the characteristics of a high pressure arc, and the function of providing infra red radiation.

The utility of my sources is to be found primarily in therapeutic and treatment work,-

though by no means confined thereto. My sources are useful in any application where a high intensity source of ultra violet radiation is desired along with a'considerable quantity of radiation in the infra red region of the spectrum.

Additional objects of my invention are the provision of arelatively inexpensive source of radiations which is economical to manufacture, small in size and convenient in use. It is an object of my invention to provide a source in which the enclosed are devices and the ballast means form a single compact unit, suitable for use in refiectors and supports of a wide variety of types for therapeutic or other uses. It is an object of my invention to provide a source in which the various parts are so constructed and arranged that a single pole, single. throw switch may be used as the starting means either in conjunction with another switch in the main. power leads, or with no switch at all in instances where the interruption of the operating current may be effected bythe removal of a plug from a socket or the like. Again it is an object of my invention to provide a strong, compact structure which may be handled as a unit and installed in or removed from a relatively simple support and. reflector means by an operation akin to "the use ofa bayo- Reference is made to the drawing, forming a part hereof and in which: s

Figure v1 is a plan view, partially in section, of the exemplary embodiment of my device.

Figure 2 is a schematic representation of the device, together with a wiring diagram.

Figure 3 is a perspective view with parts section of one of the ceramic end elements of the device.

Briefly in the practice of my invention I provide an enclosed arc device proper, including an envelope pervious to ultra violet radiation, containing a rarefied gas such as argon or the like, and a quantity of mercury such that at relatively elevated temperatures the pressure in the envelope will rise substantially, to give the operating characteristics of a high pressure arm. My invention is not limited to the degree of rise in temperature in the envelope due to the vaporization of mercury or similar vaporizable substance; but in operation, the internal pressure in my sources frequently rises to a point approaching atmospheric pressure. The envelope, of course, contains suitable and suitably interspaced electdodes for the starting and operation of the arc; and in the broader aspects of my invention the shape, form or location and characteristics of these electrodes do not constitute a limitation. I also provide sleeve-like members surrounding ther ends of the envelope and formed of some suitable insulative and heat resistant substance. In

actual practice I employ ceramic sleeves although} they may be made of other materials. Resistance wires are held in or upon these sleeves. These wires serve as a ballast means for the arc and are connected into the operating circuits thereof as will hereinafter be explained. The sleeves are heated by the wires, and in turn heat the ends of the envelope to'the extent of increasing the vaporization ofthe mercury therein and consequently increasing the working pressure of the arc. Moreover, the heat generated by the resistance elements ,on the sleeve furnishes a cury would normally occur. I am, however, not

shall now describe an exemplary embodiment;

limited to the precise structure shown. Instead of using two sleeves, oneson each end of the light source, I may employ a single sleeve which bears sufllcient resistance wire or the like to act as the ballast for the source. With sources oi different shape I may of course employ a sleeve or sleeves of appropriate shapes and in sources where all of the leads for power and starting leave the envelope at one end, I may employ a sleeve only at the end where condensation of the vaporized mercury is most likely to occur. Again, with tubular sources I may provide a sleeve which surrounds the source and is of the same length or longer, but is cut away at one side over all or a substantial part of the actual length of the are.

In the specific embodiment of my invention I have provided an envelope I, formed of material translucent to ultraviolet radiation. Such an envelope may be formed of quartz or of Corex glass or of other suitably pervious materials, but preferably it should be of a material capable of withstanding relatively high heat without melting or softening. Preferably it will have a press 2 at each end through which a series of leads for the electrode structures will be passed and sealed. The envelope will be filled with argon or other suitable rare gas at a rarefied pressure (when the temperature is room temperature, e. g. at a pressure of 10 mm. of mercury). The envelope will also contain a small quantity of mercury or other vaporizable material controlling the spectrum of the are, as indicated at 3.

As I have heretofore said, in the broadest aspect of my invention the nature of the electrode structures do not constitute a limitation. I prefer to provide main electrode structures and supplementary electrode structures, which latter structures are coated with electron-emissive substances. The electron-emissive substances may be located on a sleeve or support which in turn is heated by a filament; or they may be located directly upon a filament. electrodes need not be activated and need not be .filaments. In the particular exemplary embodiment of the invention, however, I prefer for manufacturing convenience to use filaments both as primary and secondary (or starting) electrodes and to coat at least the latter filaments with electron-emissive substances such as oxides of the rarer metals. Such electron-emissive substances are now well known in the art.

Accordingly, I have shown in my drawing at each end a pair of filaments, one of these, indicated at 4 and 4a, is a filament employed for initial ionization primarily and the other, indicated at 5 or 5a, constitutes the main arc electrode and (since it is not employed as a resistance filament) may be made as heavy as may be required for satisfactorily long life under the operation of the arc. The starting filaments 4 or 4a in the exemplary embodiment of the invention are coated with the electron-emissive substance,

' while the other filaments need not be and prefer ably are not.

The primary or are 55 the starting 9; and the bodies of the sleeves are perforated 10 sleeves may be notched as at II and II for the passage of the terminal portions of theresistance wires. One side of the sleeves is preferably fiattened as at l2 and is perforated for the reception of a pair of bayonet terminals 13 and I4 or their 15 equivalents. To one of these bayonet terminals I attach one end of the resistance wire in each sleeve. To the other I attach one of the leads I! of the starting filament 4 or 411. The other and lid of the resistance wire it is connected to leads :0 l1 and I8 respectively of a starting filament 4 or 4a and a main arc electrode filament 5 or in.

The sleeves 6 and I are not perforated over the area of the flattening l2. In order to hold the sleeves in proper relationship I prefer to provide a metal strap I! the ends of which are attached respectively to the flattened portions of the two sleeves as by means of screws 20 or in any other suitable way. Centrally of the strap I! I prefer to provide a metal hanger 2| which may be employed to support the structure and relieve the bayonet coupling means from strain. As shown, the ends of the envelope are located in and supported by the sleeves. -I prefer to provide caps or covers for the outer end'of each sleeve. These caps are shown at 22 and may be cup shaped 4., ofthe power terminals (through bayonet connection in the exemplary embodiment). The other end of each resistance I6 is connected to an end both of filaments 4 and I or of filaments 4a and 5a. The other ends of filaments 49nd 4a are connected by leads 28 and 21 to a single throw, single pole switch 22. It will be observed that when power is initially applied at the points 24, 25 a series circuit is formed (when switch- 28 is closed) including a resistance It, filament 4, filament 4a, and the other resistance It. The filaments 4 and 4a are thus energized and begin to glow, causing the electron-emissive substances on their surfaces to become activated and to ionize the surroundin I have show each of the filaments as having so atmOsPhere with?! the envelope AS the two leads passing through the press, and attached to the filaments at either end. I have already indicated that the filaments which form the main arc electrodes are not operated as electrical resistors in the sense of incandescent filaments. Consequently the leads at one end of these filaments need not be employed in the electrical circuits; but areuseful as supports for the filaments.

Surrounding each end of the enclosed arc source which I have just described, I position insulative sleeves 6 and I. These are in the form of hollow cylinders, and are shaped to slip over the ends of the envelope.- At each end these tion proceeds, trigger arcs are formed between portions of the starting filament which are at different electrical potentials respecting each other, due to the resistances of the filaments themselves. Under some circumstances supplementary or starting arcs may be formed between the starting filaments and, portions of the adjacent main electrode filaments depending upon whether the filaments are so connected into the electrical circuit as to provide sufilcient differences in potential between adjacent .parts thereof. The trigger or starting area so formed enhance and spread the ionization of the gases in the envelope to the extent that, after a short sleeves are providedwithannular grooves 8 and period of oper ti n. if he wi h 24 be p n a main arc will pas between electrode elements i and a. The switch 28 may be a hand switch; but automatically operating, time delay switches of a thermostatic or other type may be employed,

if desired.

When the main arc has been struck, there will be a short period before the arc begins to operate at its full intensity as a high pressure arc. During this period additional mercury is being vaporized both by the heat of the arc. and also by the heat applied to the ends of the envelope by the resistance coils in sleeve members i and I. The heat generated by these members will .be suiiicient to maintain a relatively high pressure in the envelope during operation both by contributing to the vaporization of mercury and by preventing concentration thereof in those portions of the envelope furthest from the high intensity arc. Also as I have indicated, the sleeve members 8, I will give off quantities of infrared radiation useful in therapeutic treatments.

It will be understood from the disclosure which I have made above that I have provided a relatively Simple self contained unit which embraces all of the operating elements of a source of ultra violet and infrared radiations excepting the switch 28, a main switch if desired and a-reflector (which is a usual and useful provision in connection with sources for therapeutic treatments). I prefer to provide in connection with my units a reflector (not shown) which will be mounted upon a suitable support, which will carry the receptacle parts of bayonet connectors to receive the connection prongs l3, H, which will preferably bear a hook-like member to engage the suspension means 2|, and which will contain appropriate wiring for power leads and for the switch 28- or its equivalent, either as part of the reflector itself or as part of the mounting therefor. It will be noted as an advantage of my structure that the reflector and supportcan be relatively simple and inexpensive, and that such wiring as is associated with it can likewise be simple and inexpensive; and further that the replacement andrenewal of light sources in the reflector is simple, rapid and convenient, and aflects the replacement and substitution not only which is short and of such length that heat apand embracing the ends of said envelope from substantially the position of said electrodes outwardly, leaving the portion of said envelope located substantially between said electrodes free forthe emission of radiation, said portion of said envelope located substantially between said electrodes providing a path for an arc discharge one at least of the filaments of each pair being coated with electron emissive substance, connections between certain of said leads and said ballast means; and contact means associated with and supported on each of said sleeves whereby starting and operating current may be applied.

to said arc device.

3. The structure claimed in claim 1 wherein said electrode means each include a pair of filaments mounted on leads passing through a press, one at least of the fllamentsnof each pair being coated with electron emissive substance, connections between certain of said leads and said ballast means, and contact means associated with and supported on each of 'said sleeves whereby starting and operating current may be applied to said are device, said sleevesarranged to engage and support said envelope and being closed at their ends by cap members. a

. one at least of the filaments of each pair bein of the envelope proper but of the associated parts including the ballast means for the arc.

Modifications may be. made in my invention without departing from the spirit of it. In particular, but without limitation, it will be understod that modifications may be made in the shape, size and contour of the sleeves as well as the manner of associating the resistance :wires therewith. While I prefer the form shown in which the resistance wires are essentially enclosed it will be understood that they may, if desired, be wound about the sleeves or otherwise disposed thereon, and further that for some uses wires as such may be dispensed with and the sleeves themselves made of some suitably electrically resistive but highly heat resistant material.

Having thus described my invention what I claim as new 'and desire to secure by Letters Patent is:

1. In a high pressure, enclosed ultra-violet arc source, the combination of an envelope of substantially cylindrical form at least at its ends, electrode assemblies including means for ionizing an atmosphere within said envelope located adiacent said ends, an ionizable atmosphere in said envelope, a quantity of vaporizable metal therein,

coated with electron emissive' substance, connections between certain of said leads and said ballast means. and contact means associated with eachof said sleeves whereby starting and operating current may be applied to said are device, said sleeves arranged to engage and support said envelope and being closed at their ends by cap members, and a rigid bar-like connection between said sleeves fastening said sleeves together and providing means whereby the assembled are device may be supp rted.

5. In combination in'a source of ultra-violet radiations, elongated, closed envelope pervious to 'ultraviol radiations, containing electrodes,

and containing a quantity of mercury sufllcient in unit, said sleeves surrounding end portions of the envelope including portions thereof in which said electrodes are located, but spaced from each other sufllciently to uncover said envelope for substantially the length 01' the main are discharge there- 6. Apparatus as claimed in claim 5 in which and sleeves oi refractory material surrounding" d sleeves are. annul r. in form, Iroov'ed at the ends, and longitudinally perforated between said grooves, said resistance means comprisin: resistance wire passing back and forth through said perforations and being essentially enclosed within said sleeves,-

7. Apparatus as claimed in claim 5 in which said sleeves are connected by a suspension means for said unit, which suspension means is in the form of an elongated member with an nd portion attached to each sleeve.-

8. Apparatus as claimed in claim 5 in which said sleeves are connected by a suspension means' are cap members eoverins the outer ends'ot said sleeves.

9. Apparatus as claimed in claim .5 in which said sleeves are connected by a suspension means for said unit, which suspension means is in the form of an elongated member with an end portion attached to each sleeve, and in which there are cap members covering the outer ends or said sleeves, said terminal connection means comprising bayonet connectors and said suspension means comprising enzasement means which can be caused to come into rocking enzazement with supporting means in position to permit insertion of said bayonet means into bayonet receptacles.

' GEORGE B. SPERTI. 

